Lymph nodes are points of coordination for the immune system, where T cells of the adaptive immune system are presented with antibodies that match target molecules, in effect given instructions as to what to attack next. Calling a structure made of biomaterials and decorated with antibodies an "artificial lymph node" does get the point across, but this is a far cry from, say, a lymph node organoid that shares a similar structure and set of cell populations with a natural lymph node. Still, the artificial structure does serve this one purpose, to instruct T cells. Researchers here envisage implanting a lymph node substitute as a part of a T cell therapy for cancer, using appropriate antibodies to ensure that the T cells will aggressively attack cancerous cells.
Lymph nodes - tiny glands throughout the body, mainly in the neck, armpits and groin - are part of the immune systems of mammals, including mice and people. They number in the hundreds so that immune cells in one area of the body don't have to travel far to alert the immune system to impending danger. "They are a landing spot where T-cells, the immune system's fighting cells, lay dormant, waiting to be activated to fight infections or other abnormal cells. Because cancers can trick T-cells into staying dormant, the artificial lymph node was designed to inform and activate T-cells that are injected alongside the lymph node." To create the artificial lymph node, the scientists used hyaluronic acid, a substance found naturally in the body's skin and joints. Because of its properties, hyaluronic acid is often used in biodegradable materials such as wound healing patches meant to be implanted or applied to the body. Among those properties, hyaluronic acid can connect with T-cells via a cell surface receptor. Researchers used hyaluronic acid as the scaffolding, or base, for their new lymph node, and added MHC (major histocompatibility complex) or HLA (human histocompatibility antigen) molecules, which rev up T-cells and other immune system components. Then, they also added molecules and antigens common to cancer cells to "teach" T-cells what to look for. "By adding different antibodies to the artificial lymph node, we have the ability to control what the T-cells are being activated to search for. An advantage to this approach over other cell-based therapies such as CAR-T is fewer manufacturing steps. Current cell-based therapies require extracting T-cells from a patient, manipulating them outside of the body to recognize a particular type of cancer, and injecting them back into the patient. In our approach, we inject T-cells along with an artificial lymph node, and the T-cells get primed and educated by the artificial lymph node inside of the body. Then, the T-cells can travel anywhere to destroy cancer cells."
